A senior al-Qaeda leader in Afghanistan, Abu Laith al-Libi, has been killed, Western counter-terrorism officials have told the BBC.

News of his death emerged on a website used by Islamist groups. Ekhlaas.org said he had "fallen as a martyr".

Pakistan says it cannot confirm reports that Libi was killed by a US missile strike in Pakistan on Tuesday

Libi is believed to have behind an attack at an Afghan air base last year while the US vice-president was there.

Most analysts say Libi's death would be a blow to al-Qaeda, both symbolically and operationally.

But the BBC's security correspondent Frank Gardner says al-Qaeda has proved itself to be resilient to individual losses and setbacks, and no-one is predicting an immediate decline in attacks in the region.

US Defense Secretary Robert Gates said he did not "have anything definitive" to say about the news, the Associated Press reported.

Al-Qaeda spokesman

Libi, 41, has appeared in a number of al-Qaeda videos. In November he appeared alongside al-Qaeda second-in-command Ayman al-Zawahri.